• Journal of fish pathology
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• v.26 no.3
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• pp.139-148
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• 2013

The genus Polydora(Polychaeta, Spionidae) includes many species well known for their activity as borers. They often become harmful invaders by reducing the growth rate and meat yield of, or inducing the mortality of commercially important mollusck, abalone, Haiotis discus hannai. In 2012, the frequency of the Polydora was observed with 5~99% in live abalone and 5.3~70.3% in dead abalone shells of abalone sea-caged aquaculture system, Korea. There are many nacreous blister in the ventral margin and inner of the infestated abalone by abalone in response to the Polydora. A worm bored two holes in the shell and come in and out for ingestion the organic matters. They are more than 40 mm in length and had outstanding palps with black bars, disc form pygidium and 4 eyespots. This is the first record for the statue of Polydora infestation of sea-caged cultured abalone, Haliotis discus hannai in Korea.

• Journal of Aquaculture
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• v.16 no.4
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• pp.257-261
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• 2003

The effects of different stocking densities on the growth of juvenile abalone, Haliotis discus hannai and water quality in the recirculating system with rotating biological contactor, were assessed. The trials were conducted using total weight 32 g juveniles abalone for 60 days at stocking densities of 5, 10, 15 kg/$m^2$. The animals were fed sufficient amounts of the pellet diet of 30.4% protein during the experimental period. Daily feeding rate (DFR) and survival rate (SR) of 5 kg/$m^2$ showed 0.76% and 85.5% those were not significantly differed 10 kg/$m^2$ showing 0.75% and 96.0% (P>0.05). DFR and SR of 15 kg/$m^2$ showing 0.38% and 31.2% were significantly lower than 5 and 10 kg/m2 (P<0.05). Daily growth rate (DGR) and feed efficiency (FE) showed the highest as 0.19% and 24.2% in 5 kg/$m^2$ the lowest as 0.05% and 14.3% in 15 kg/$m^2$ (P<0.05). According to, these results was an inverse relationship between growth and stocking density. The optimum density of juvenile abalone from this experiment is 5 to 10 kg/$m^2$ in the recirculating system.

• The Korean Journal of Malacology
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• v.28 no.4
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• pp.343-347
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• 2012

The growth rates of offspring of selected abalone (SA), Haliotis discus hannai, population for rapid growth were compared to those of offsping of the control abalone (CA) at bred under the same condition. The growth traits (shell length, shell breadth and total weight) of SA were significantly faster than those of CA at this experiment. At the 45th day and 90th day, the growth rates in shell length of SA were estimated 31.7% and 17.8% faster than those of CA, total weight of SA were estimated 43.7% and 25.6%, respectively. Moreover, the relative growth rate between shell length and total weight of SA showed significant differences higher than one in CA at 90th day. The results suggest a possibility of improving the growth rate of cultured abalone using selection techniques.

• The Korean Journal of Malacology
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• v.29 no.4
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• pp.303-311
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• 2013

This study investigated survival, falling and structural changes of foot in Haliotis discus hannai with various water temperature and salinity. Experimental conditions were composed of control with $20^{\circ}C/33.5$ psu, higher temperature group with 23, 26, 29 and $32^{\circ}C$, lower temperature group with 3, 6, 9 and $12^{\circ}C$, and different salinities group with 33.5, 26.8, 20.1, 13.4, 6.7 and 3.3 psu. Experimental period was 7 days. Survival and falling rate of the abalone exposed to 7 days at control and experimental condition of $12^{\circ}C$ and $23^{\circ}C/33.5$ psu were 100% and 0%, respectively. Mortality and falling rate of the abalone exposed to the different temperature and salinity were dose dependent by experimental condition. Histopathological changes in epithelial and muscular layer of foot showed more obvious with experimental condition of salinity decrease than different temperature condition.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.11a
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• pp.237-246
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• 2005

A tip-over test of the 1/3 scale model is conducted to verify the tip-oner analysis of a dry concrete storage cask under a hypothetical accident condition. The tip-oner analysis is executed using the velocity at each point which are determined from the initial angular velocity as the initial conditions of the model just before the impact. To confirm the structural integrity of the canister of a dry concrete storage cask, the non-detective testing such as Liquid Penetrants testing and Ultrasonic Testing are conducted. The strains and tile accelerations acquired by the tip-over test are compared with those by the analysis to verify the tip-over analysis. The lid of a storage calk are plastically deformed at the impact point. Liquid

• The Korean Journal of Malacology
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• v.29 no.2
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• pp.91-96
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• 2013

Although the method of seedling production of Haliotis discus hannai is well known, the optimum benthic diatom species as a live food at early larval stage are not fully developed. In this study three Pennales diatom species, Caloneis schroederi, Rhaphoneis sp., and Cocconeis californica were examined on settlement, metamorphosis, survival, and growth of Haliotis discus hannai larvae. The larvae fed Raphoneis sp. or C. californica showed high settlement rate with 80-82% within 48 hrs, which was significantly higher than those fed C. schroederi or mixed diets with three diatom species. The larvae fed the former microalgal species also showed higher metamorphosis rate with 32-34% than the latter species with 10-12% within 4 days. With regard to survival and growth of the larvae, single diet with Rhaphoneis sp. or C. californica had better dietary value than the mixed diets for the early larvae of H. discus hannai.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.3
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• pp.282-288
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• 2002

This study was carried out to investigate the optimum tagging method of the abalone juvenile, Haliotis discus hannai in indoor culture system from May 2000 to January2001. Tagging methods were shell drilling, copper-wire tagging at the respiratory pore and nut gluing on the shell. The attachment rates of the shell showed high in the 2- and 3 cm bolt-nut tagged groups, about over $89.5\%$, whereas shell drilling groups on the shell were about $18.5\%$. The internal coating rates tagged with bolt-nut were over $96.6\%$, while those tagged with copper wire were less than $17.1\%$. Growths in the all marked and tagged experimental groups comparing with control groups were not significantly different (p>0,05). Survivals in all tagging groups except shell drilling and nut gluing groups in the 5 cm abalone were over $95\%, Accordingly, all juvenile groups were not affected by the tagging methods in terms of the growth and survival on the abalones. Based on these results, the micro bolt-nut tagging was the most effective method in abalone.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1031-1037
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• 2021

The frequency of marine accidents of vessels in Korea is steadily increasing and it is concentrated on small vessels with less than 10 tons of gross tonnage. Therefore, preventing capsizing accidents in small vessels is important to reduce the cost in terms of human and property damage due to such accidents. However, research on the seakeeping performance of small vessels has been insufficient, and there are no domestic and international regulations on seakeeping performance. Therefore, in this study, capsizing accidents caused by poor loading conditions were investigated by examining the adjudications of the small vessels in which the capsizing accidents occurred. Hydrostatic calculations and seakeeping performance analysis were performed for a representative vessel. A vessel generally performs a six-degree-of-freedom motion during operation. In this study, the response amplitude operator and response spectrum of a representative vessel were calculated to determine the roll motion. Moreover, a short-term statistical analysis of the vessel according to the loading conditions was performed for the wave stationary status for 3 h. From the results, it was estimated that, when the loading condition of a small vessel is poor, its roll motion increases, greatly reducing its stability.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06c
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• pp.277-279
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• 2006

본 논문에서는 Wireless Sensor Networks(WSNs)에서 에너지 소모를 줄이기 위해 사용되는 In-network processing에 대하여 보안이 강화된 레벨 키 기반의 Infrastructure를 설계하여 노드의 전복 공격에 대해 안전한 패킷 포워딩을 보장하는 프로토콜을 제시한다. 이러한 계층적 구조를 가지는 보안 Framework는 노드의 추가 혹은 퇴거가 발생했을 때 Re-keying 비용을 획기적으로 줄일 수 있다. 시뮬레이션 결과, 전체 네트워크 중 전복된 노드가 40%를 차지할 때, 제안된 프로토콜을 사용하게 되면 약 3%의 추가적인 라우팅 오버헤드 비용으로 15%의 향상된 종단간 패킷 전송률을 보여준다. 또한 Re-keying을 할 때 OFT와 비교하여 통신비용을 현저하게 줄일 뿐만 아니라 서버의 도움 없이 키를 업데이트 하기 때문에 분산환경에 적합한 특징을 갖는다.

• The Korean Journal of Malacology
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• v.32 no.4
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• pp.249-254
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• 2016

The purpose of this study is to estimate genetic parameter and growth traits by sex of Pacific abalone, Haliotis discus hannai. The abalone 10 family produced using 1:1 mating system of male and female for analyses of sex ratio and growth traits (shell length, shell width, and total weight) by sex. Overall mean in phenotypic traits at 30-month-old showed 85.01 mm of shell length, 57.49 mm of shell width and 73.34 g of total weight respectively. The sex ratio (female : male) was 1:0.93 (n = 191:177). The values of growth traits by sex showed significant difference (P < 0.05). The each value of female growth traits were shown to be higher than the values of male growth traits. The heritability of growth traits by sex were estimated that the heritability of female growth traits are higher than male that. The results suggest a possibility of improving the growth of cultured abalone using selection breeding by sex.